The data series are calculated as the average of annual mean concentrations for groundwater bodies/river stations/lake stations in Europe. Only complete series after inter/extrapolation are included (see indicator specification). The number of groundwater bodies/river stations/lake stations included per country is given in the notes below the individual substance charts.

Stations showing a statistically significant decrease (green), increase (red) or no trend (grey) of winter dissolved inorganic nitrogen (DIN) concentrations within the period 1985 to 2012. Selected stations must have data at least in the period 2007 to 2012 and at least five years data in all.

Stations showing a statistically significant decrease (green), increase (red) or no trend (grey) of winter oxidised nitrogen concentrations within the period 1985 to 2012. Selected stations must have data, at least, in the period 2007-2012 and must have at least five years data in all.